[Python-checkins] [3.7] Fix elif start column offset when there is an else following (GH-17596) (GH-17601)

[Pablo Galindo]

https://github.com/python/cpython/commit/4b75466f5a539021217cff18bc248c1593cee262
commit: 4b75466f5a539021217cff18bc248c1593cee262
branch: 3.7
author: Pablo Galindo <Pablogsal at gmail.com>
committer: GitHub <noreply at github.com>
date: 2019-12-14T10:55:00Z
summary:

[3.7] Fix elif start column offset when there is an else following (GH-17596) (GH-17601)

(cherry picked from commit 5936a4ce914d42af97b9238e5090dedc8d5b0bd2)

Co-authored-by: Lysandros Nikolaou <lisandrosnik at gmail.com>

files:
M Lib/test/test_ast.py
M Python/ast.c

diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py
index 0daa2f77dc718..830fb58a02b66 100644
--- a/Lib/test/test_ast.py
+++ b/Lib/test/test_ast.py
@@ -66,6 +66,8 @@ def to_tuple(t):
     "if v:pass",
     # If-Elif
     "if a:\n  pass\nelif b:\n  pass",
+    # If-Elif-Else
+    "if a:\n  pass\nelif b:\n  pass\nelse:\n  pass",
     # With
     "with x as y: pass",
     "with x as y, z as q: pass",
@@ -606,6 +608,12 @@ def test_elif_stmt_start_position(self):
         self.assertEqual(elif_stmt.lineno, 3)
         self.assertEqual(elif_stmt.col_offset, 0)
 
+    def test_elif_stmt_start_position_with_else(self):
+        node = ast.parse('if a:\n    pass\nelif b:\n    pass\nelse:\n    pass\n')
+        elif_stmt = node.body[0].orelse[0]
+        self.assertEqual(elif_stmt.lineno, 3)
+        self.assertEqual(elif_stmt.col_offset, 0)
+
     def test_literal_eval(self):
         self.assertEqual(ast.literal_eval('[1, 2, 3]'), [1, 2, 3])
         self.assertEqual(ast.literal_eval('{"foo": 42}'), {"foo": 42})
@@ -1244,6 +1252,7 @@ def main():
 ('Module', [('While', (1, 0), ('Name', (1, 6), 'v', ('Load',)), [('Pass', (1, 8))], [])]),
 ('Module', [('If', (1, 0), ('Name', (1, 3), 'v', ('Load',)), [('Pass', (1, 5))], [])]),
 ('Module', [('If', (1, 0), ('Name', (1, 3), 'a', ('Load',)), [('Pass', (2, 2))], [('If', (3, 0), ('Name', (3, 5), 'b', ('Load',)), [('Pass', (4, 2))], [])])]),
+('Module', [('If', (1, 0), ('Name', (1, 3), 'a', ('Load',)), [('Pass', (2, 2))], [('If', (3, 0), ('Name', (3, 5), 'b', ('Load',)), [('Pass', (4, 2))], [('Pass', (6, 2))])])]),
 ('Module', [('With', (1, 0), [('withitem', ('Name', (1, 5), 'x', ('Load',)), ('Name', (1, 10), 'y', ('Store',)))], [('Pass', (1, 13))])]),
 ('Module', [('With', (1, 0), [('withitem', ('Name', (1, 5), 'x', ('Load',)), ('Name', (1, 10), 'y', ('Store',))), ('withitem', ('Name', (1, 13), 'z', ('Load',)), ('Name', (1, 18), 'q', ('Store',)))], [('Pass', (1, 21))])]),
 ('Module', [('Raise', (1, 0), ('Call', (1, 6), ('Name', (1, 6), 'Exception', ('Load',)), [('Str', (1, 16), 'string')], []), None)]),
diff --git a/Python/ast.c b/Python/ast.c
index d1b87d888e5c2..9d8a3544bdfc9 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -3601,8 +3601,8 @@ ast_for_if_stmt(struct compiling *c, const node *n)
 
             asdl_seq_SET(orelse, 0,
                          If(expression, suite_seq, suite_seq2,
-                            LINENO(CHILD(n, NCH(n) - 6)),
-                            CHILD(n, NCH(n) - 6)->n_col_offset,
+                            LINENO(CHILD(n, NCH(n) - 7)),
+                            CHILD(n, NCH(n) - 7)->n_col_offset,
                             c->c_arena));
             /* the just-created orelse handled the last elif */
             n_elif--;